1. Field of the Invention
The present invention relates to a sheet feeding apparatus provided in an image forming apparatus, such as a copying machine, a facsimile machine, a laser beam printer, or a multifunction peripheral, and an image forming apparatus including the same.
2. Description of the Related Art
In the past, an image forming apparatus, such as a printer or a copying machine, has included a sheet feeding apparatus which separates sheets stacked on a sheet cassette or a sheet tray one by one and fed the separated sheet to an image forming portion. In such a sheet feeding apparatus, various separating methods are employed in a separating portion for separating the sheets one by one. For example, there is known a so-called slope separation method that separates a sheet by buckling a sheet while abutting a front edge of a sheet fed by feeding rollers against a separation slope in a feeding direction (see U.S. Pat. No. 5,622,364).
Recently, in the offices or homes, there has been an increasing demand for using a low-price small-sized printer or copying machine to be installed on a desk in use. In order to achieve this demand, one countermeasure is to further reduce the size and cost of a sheet feeding apparatus provided in a printer or a copying machine.
In a case where the sheet feeding apparatus employing the slope separation method described in Patent Literature 1 is used as the countermeasure, it is also easy to reduce the size of the low-cost apparatus. However, there is a problem that it is difficult to achieve the compatibility between separation performance for a sheet having a low rigidity (weak stiffness) (sheet having a thin thickness) and conveyance performance for a sheet having a high rigidity (strong stiffness) (sheet having a thick thickness) is difficult.
The present invention is directed to provide a sheet feeding apparatus capable of exhibiting stable separation feeding performance in both of a sheet having a low rigidity and a sheet having a high rigidity in a slope separation method, and an image forming apparatus including the sheet feeding apparatus.